Chikage Izumi is a female student and a primary character. She is introduced as a classmate of Akatsuki Ousawa and Myuu Ousawa at JPN Babel, a special academy for young people who have returned from fantasy worlds. Her birthplace is Earth. On her first day meeting the protagonists, she approaches them in a friendly manner, though her initial intention was simply to avoid getting into trouble with another student. Chikage has a tomboyish appearance, characterized by short brown hair and amber or orange eyes. Her typical age is around sixteen, and her combat style makes use of a longbow.

Chikage possesses a kind, cheerful, and happy-go-lucky personality, almost always seen with a smile on her face. She is notably open and shameless about her attraction to other girls, and her behavior often includes perverted or flirtatious comments toward female characters such as Myuu and Kuzuha Doumoto. As the story progresses, she develops romantic feelings for Akatsuki and becomes part of his harem, implying that she is likely bisexual but had primarily acted on her attraction to women previously. Beneath her jovial exterior, her motivation for befriending others comes from a deep-seated desire to be needed. She seeks out girls who share her feelings of loneliness, listening to their troubles and offering comfort, which often leads to these relationships becoming romantic.

In the story, Chikage serves as one of Akatsuki and Myuu's first and most loyal allies. She teams up with them, along with Kuzuha Doumoto and others, during the ranking matches at Babel. After the revelation of Myuu's true identity, Chikage accompanies the group to the world of Alayzard, becoming one of the key members of their party. She is fiercely protective of her friends, demonstrated when she shields Myuu from a Cockatrice and later when she suffers severe injuries while defending Kuzuha from an enemy named Phil Barnett. Following her return to Alayzard as a returnee a second time, her power increases substantially. After the independent organization Noah is established, she holds the position of Third Deputy Commander.

Chikage's notable abilities center on the element of water, which she wields in combination with her longbow for long-range attacks. A unique and advanced technique involves her manipulating ambient hydrogen, allowing her to compress and detonate the gas to create a field of explosions that can completely surround her target. Her class ranking at Babel is Class A, having previously been Class B.